Psychophysical studies of imagined stimuli: Testing the limits of self-knowledge.


There is a coalescing trend in several areas of pain research. Studies endeavoring to measure the extent to which individuals differ in ascribing pain intensity to noxious stimuli are occurring in areas of pain research as diverse as self-assessment questionnaires, genetics, functional neuro-imaging and psychophysics. The article in this issue of Pain by Ruscheweyh et al. [7] highlights on two important points relating to the measurement of individual responses to pain. The first is a point of terminology, the second is a point of critical importance in pain neurobiology: the extent to which responses to imagined stimuli predict clinically relevant pain outcomes [3]. A variety of terms have been applied to describe inter-individual differences in responsiveness to controlled noxious stimuli and painful experiences: pain sensitivity, pain hypersensitivity, pain responsivity, pain perception, pain reactivity, pain responsiveness and central pain processing are among those commonly used. Of these, ‘pain sensitivity’ is the term most widely used to describe the tendency of individuals to vary in the extent to which they respond to noxious stimuli. A survey of this term in Pubmed indicates that ‘pain sensitivity’ was used infrequently prior to 1973 but became the subject in many studies from the late 1970s onwards [2]. A related term, pain hypersensitivity, presumably indicating abnormally increased sensitivity to pain, is much less frequently used. There are many instances however, where ‘pain sensitivity’ is not chosen by the authors to describe the responsiveness of individuals to pain. The potential reasons for this may be several. For example, the broader use of ‘sensitivity’ in discourse carries the connotation of emotionality. In addition, sensitivity in other technical applications focuses on assessing the capacity to distinguish the presence of especially small stimulus perturbations. The term ‘pain perception’, also widely used since the 1970s, carries the same implicit meaning ofmeasuring responses to small amounts of pain. The term ‘pain reactivity’ seems to have had a history in the psychological literature of the mid-twentieth century but found later application to describe both biobehavioral and neurohumoral responses in animal andhuman studies of pain [8]. Theuseof the term ‘pain responsivity’ began in 1981 and becamemore widespread in the 1990s. Presumably, the word responsivity was chosen to reference the notion that responsivity ismeasured by assessing responses to a particular nociceptive stimulus. One reason that broader use of this term may not beoptimal is that in engineeringapplications, responsivityhas aparticular meaning: it is the derivative (or slope) of the stimulus–response curve. Given the limitations described here, it is timely to re-consider the value of ‘pain responsiveness’ as a term of reference. ‘Pain responsiveness’ was first used in published pain research in 1977 [5] and has been subject to a steady stream of citations since that time. Pain responsiveness appropriately conveys the quality of being responsive to pain and directly alludes to the process of

DOI: 10.1016/j.pain.2009.07.041

Cite this paper

@article{Murinson2009PsychophysicalSO, title={Psychophysical studies of imagined stimuli: Testing the limits of self-knowledge.}, author={Beth Brianna Murinson and David Yarnitsky}, journal={Pain}, year={2009}, volume={146 1-2}, pages={13-4} }